Photographic processing apparatus

ABSTRACT

It is known to apply processing solution to photographic material using a high speed moving surface. High speed rotating drums have been used to transfer processing solution from a reservoir to the material. Horizontal belts are also known. However, such arrangements require large volumes of processing solution in order to operate effectively. Described herein is a processor comprising a vertically mounted high speed belt which both transfers processing solution from a reservoir onto photographic paper being processed, and provides agitation at the paper surface. Two transport belts are provided, one on either side of the belt to assist in the transport of paper through the apparatus. An arrangement according to the invention has the advantages that only low volumes of processing solutions are required, good surface agitation is provided, and it can be fitted into conventional photographic processing apparatus.

FIELD OF THE INVENTION

This invention relates to photographic processing apparatus and is moreparticularly, although not exclusively, concerned with the applicationof photographic processing solutions to the material to be processed.

BACKGROUND OF THE INVENTION

Processing solutions have been applied to photographic materials usingvarious methods. One method has been to use a high speed moving surface.It has been known to use high speed spinning drums to provide the highspeed moving surface. In these arrangements, processing solution isretained in a tray through which the high speed moving surface passes.As the surface passes through the tray, it lifts processing solution outof the tray and carries it to a position where the solution is appliedto the photographic material being processed.

In one arrangement where a high speed spinning drum is used, a messblanket is used to hold the material against the drum surface. The drumis heated by hot water inside it. In another arrangement, a moving beltis used to transport the material across the surface of the spinningdrum.

U.S. Pat. No. 3,192,846 discloses an arrangement in which photographicmaterial is transported through processing apparatus on fluid layersformed one either side of the material. These fluid layers act asbearings for the material to prevent it becoming damaged duringtransportation. The fluid layers are applied by conduits positioned oneither side of the material. The material is driven through theprocessing chamber by drive rollers positioned at either end. Anotherarrangement is also described in which rollers are used to guidematerial over a moving applicator belt as described above. Agitation isachieved when the linear speed of the applicator belt greatly exceedsthe linear speed of the material being fed through the processingchamber.

In the applicator belt arrangements decribed above, large volumes ofprocessing solution are required. This means that the processingsolutions used need to be stable for relatively long periods of time.

In redox amplification processes where colour materials are developed toproduce a silver image (which may contain only small amounts of silver)and then treated with a redox amplifying solution to form a dye image,the amplifying solution contains both an oxidising agent and a reducingagent and it is therefore inherently unstable. That is to say, unlike aconventional colour developer solution, amplifier solutions willdeteriorate in less than an hour even if left in a sealed container. Thebest reproducibility for such a process has been obtained by using a"one shot" system, where the oxidant is added to the developer and thesolution mixed and used immediately (or after a short built in delay)and then discarded. Such a "one shot" system cannot be used with theapplicator belt arrangements described above as a relatively largevolume of processing solution is required. Furthermore, the "one shot"system leads to the maximum solution usage possible with maximumeffluent and maximum chemical costs. As a result the whole system isunattractive especially for a minilab environment where minimum effluentis required. It is believed that it is these shortcomings that haveinhibited commercial use of this process.

It is therefore an object of the present invention to provide processingapparatus incorporating an applicator belt which uses small amounts ofprocessing solution, and therefore overcomes the disadvantages mentionedabove.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is providedphotographic processing apparatus for processing photographic materialcomprising an applicator belt for applying processing solution to thephotographic material characterized in that at least one transportsurface is provided for transporting the material over the surface ofthe applicator belt and in that the applicator belt lies in asubstantially vertical plane.

Advantageously, a reservoir is provided for storing processing solution.The applicator belt removes solution from the reservoir for applicationto the photographic material as it moves through the reservoir. Thereservoir has a volume such that replenishment rate of the processingsolution is at 1east three times the reservoir volume during the usefullife of the processing solution.

By this arrangement, only a small amount of processing solution isrequired. This has the advantage that unstable processing solutions, forexample those used in redox amplification processing can be used.

It is preferred that the at least one transport surface comprises asurface of a transport belt which is positioned adjacent the applicatorbelt. In the preferred embodiment of the invention, two transport beltsare provided which are positioned one on either side of the outsidesurface of the applicator belt. This has the further advantage in thatapparatus according to the invention can easily be fitted into standardphotographic processing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference will nowbe made, by way of example only, to the accompanying drawing, the singleFIGURE of which shows a schematic cross-sectional view of an applicatorbelt arrangement constructed in accordance with the invention.

DETAILED DESCRIPTION

A processor constructed according to the present invention isillustrated in FIG. 1. The processor comprises a centrally mountedapplicator belt 10 which is carried by a pair of rollers 12, 14. At thelower end of the belt 10, a hollow block 16 is positioned, the uppersurface 18 of the block being shaped to define a reservoir 20.

The reservoir 20 is heated by hot water, the hot water flowing into andout of the block 16 at 22 and 24 respectively. Processing solution 26 ismaintained at a predetermined level within the reservoir 20 as indicatedby arrow `X`, and is added to and removed from the reservoir 20 byinlet/outlet 28.

The lower roller 14 dips into the reservoir 20 and processing solution26 is picked up and carried round by the applicator belt 10.

A transport belt 30, 32 is mounted on each side of the applicator belt10 as shown. Each belt 30, 32 is carried by a pair of vertically spacedrollers 34, 36, 38, 40. The lower rollers 36, 40 are positioned adjacentthe reservoir 20. Guides 42, 44 are provided at the lower ends of thetransport belts 30, 32 to direct the photographic paper to be processedinto and out of the reservoir 20.

A central roller 46, positioned above the upper roller 12, helps toguide the paper into and out of the processor 1 in conjunction withinlet guide rollers 48, 50 and outlet guide rollers 52, 54.

In use, processing solution 26 is added to the reservoir 20 through theinlet/outlet 28. Photographic material, for example paper, is fed intothe processor 1 through inlet rollers 48, 50. The paper is thendirected, by roller 46 and transport belt 30 in to the space between theapplicator belt 10 and transport belt 30 itself. The transport belt 30holds the paper against the applicator belt 10 and drives it through theprocessor 1 in a downward direction until guide 42 is reached.

Here, the paper is directed into the processing solution 26 retained inthe reservoir 20 by the guide 42. The surface 18 of the block 16defining the reservoir 20 guides the paper through the processingsolution 26 around roller 14 and that portion of the applicator belt 10adjacent the roller at that instant towards guide 44. The paper is thendirected upwards into the space between the applicator belt 10 and theother transport belt 32. The belt 32, like belt 30, holds the paperagainst the applicator belt 10 and drives it upwards away from thereservoir 20 towards the roller 46. Roller 46 directs the paper throughoutlet rollers 52, 54 to the next stage in the processing apparatus.

In the processor shown in the drawing, the paper being processed isretained on the transport belts 30, 32 by means of suction. This meansthat the paper is travelling at the same linear speed as the transportbelts 30, 32. The applicator belt 10 has a much higher linear speed andcarries a layer of processing solution on its outside surface.

The paper surface being processed is maintained in contact with theliquid layer, and agitation of the surface is provided by shear producedacross this liquid layer due to the difference in linear speed betweenthe applicator belt 10 and the transport belts 30, 32.

The transport belts 30, 32 have linear speeds of approximately 25 mms⁻¹,whilst the applicator belt 10 has a linear speed in the range of 0.15 to1.02 ms⁻¹ (30 to 200 ftmin⁻¹).

As only a small volume of processing solution 26 is contained in thereservoir 20, the turnover of prescessing solution can be very short,for example less than 10 minutes. This means that equilibrium can beapproached in 30 minutes, and in this example the solution stability ofthe unreplenished working developer gave acceptable sensitometry over aperiod of 30 minutes. The reservoir 20 retains a volume of processingsolution between 100 and 150 ml prior to start up of the applicator belt10. Naturally, as the belt 10 moves processing solution is removed fromthe reservoir 20 and applied to the material being processed.

As only low volumes of processing solution are used in the processor,only small volumes of solution need to be discarded if the processor isstopped for any reason, for example cleaning. This reduces the effluentproduced.

It is preferred that the applicator belt 10 has a patterned surface toassist in the take-up of processing solution from the reservoir 20. Thepatterned surface also assists in the provision of agitation to thepaper surface.

As the processor is arranged substantially vertically, it can easily befitted into standard processing apparatus, for example, a Noritsu 801 orKodak system 25 processor.

Although the invention has been described with reference to theprocessing of photographic paper, it is not limited to such use only.

Furthermore, the processor according to the present invention is notlimited to use for processing material in a continuous web, but couldequally well be used for sheets of material.

The processor according to the invention can be used in any environmentwhere good agitation is required.

In the embodiment described, the emulsion surface of the paper isinnermost. However, it may be desirable that the emulsion surface isoutermost. In such a case, the two outer belts 30, 32 are now high speedapplicator belts, and the inner belt 10 is a transport belt. Reservoir20 is then replaced by a simple turnaround system comprising a singleroller and two guide members which convey the paper from a positionadjacent roller 36 to a position adjacent roller 40. Two reservoirs,each one mounted below a respective one of rollers 36, 40, are alsoprovided to supply processing solution to each one of the two applicatorbelts. These reservoirs may be either entirely separate or fluidlyconnected to one another.

We claim:
 1. Photographic processing apparatus for processingphotographic material comprising an applicator belt carried by at leasttwo rollers and said applicator belt applying processing solution to thephotographic material characterized in that at least one transportsurface is provided for transporting the material over the surface ofthe applicator belt and in that the applicator belt lies in asubstantially vertical plane and a reservoir adapted to conform to andbe spaced from a portion of one of said rollers of said applicator belt,said reservoir storing processing solution and said applicator beltremoving solution from said reservoir for application to thephotographic material.
 2. Apparatus according to claim 1 wherein thereservoir has a volume such that replenishment rate of the processingsolution is at least three times the reservoir volume during the usefullife of the processing solution.
 3. Apparatus according to claim 1wherein the reservoir has a volume to material width ratio below 20mlcm⁻¹.
 4. Apparatus according to claim 1 wherein the reservoir has avolume to material width ratio of 10 mlcm⁻¹.
 5. Apparatus according toclaim 1, wherein the at least one transport surface is provided by asurface of a transport belt which is positioned adjacent the applicatorbelt.
 6. Apparatus according to claim 5, wherein two transport belts areprovided, and are positioned on either side of and adjacent the outersurface of the applicator belt.
 7. Apparatus according to claim 5,further including a further applicator belt, each applicator belt beingsymmetrically arranged adjacent the outer surface of the transport belt.8. Apparatus according to claim 1, wherein a fluid bearing is formedbetween the applicator belt and the material being processed. 9.Apparatus according to claim 1, wherein the photographic material is insheet form.